char findTheDifference(char* s, char* t)
{
    int cnt[26];
    memset(cnt, 0, sizeof(cnt));
    int n = strlen(s), m = strlen(t);
    for (int i = 0; i < n; i++)
    {
        cnt[s[i] - 'a']++;
    }
    for (int i = 0; i < m; i++)
    {
        cnt[t[i] - 'a']--;
        if (cnt[t[i] - 'a'] < 0)
        {
            return t[i];
        }
    }
    return ' ';  
}